Method and apparatus for simultaneous use of both licensed and unlicensed wireless spectrum

ABSTRACT

A control circuit determines that a wireless portable electronic device currently being serviced via licensed wireless spectrum should also be served via unlicensed wireless spectrum and then transmits a Radio Resource Control (RRC) message to cause the wireless portable electronic device to connect to a network node operating in the unlicensed wireless spectrum. By one approach this control circuit comprises an Evolved Node-B base station in a Long Term Evolution (LTE) Radio Access Network (RAN) and the network node operating in the unlicensed wireless spectrum comprises an 802.11-compatible wireless local area network node.

FIELD OF TECHNOLOGY

The present disclosure relates to wireless portable electronic devices,including but not limited to portable electronic devices that canoperate compatibly using either licensed or unlicensed wirelessspectrum.

BACKGROUND

Wireless portable electronic devices (also referred to herein asportable electronic devices) are well known and nearly ubiquitous inmodern life. In addition to often supporting a wide variety of localand/or native functionality these devices also often transceive variouskinds of data via one or more wireless links. Examples of wireless linksinclude but are not limited to Long Term Evolution (LTE)-based radionetworks that employ licensed wireless spectrum and 802.11-compatiblewireless local area networks (WLAN's) that employ unlicensed wirelessspectrum. (As used herein, the expressions “licensed” and “unlicensed”shall be understood to refer to license-based authorization and controlas implemented and governed by a given national government(s) within itsterritory or region via a corresponding agency such as, in the UnitedStates, the Federal Communications Commission.)

Some functionality can require substantial use of a given device'swireless communications capabilities. Such substantial use, in turn, canrequire sending and/or receiving large quantities of data.Unfortunately, many licensed wireless spectrum-based networks chargeaccordingly and/or limit the amount of data that can be transceived viatheir networks. It is known in the art to rely instead upon an availablenetwork that employs unlicensed wireless spectrum when transceivinglarge quantities of data to avoid such restrictions/costs.Unfortunately, merely providing such a capability in a portableelectronic device as an available option does not necessarily meet alluser requirements and/or the needs of all application settings.

For example, to date, integration of unlicensed spectrum into anoperator's core network has been done mainly at higher layers providingmainly IP-level interworking between licensed and unlicensed spectrum.Such an approach leads to a number of corresponding problems. Peakthroughput per application, for example, is often not improved as agiven bearer/APN traffic is still routed via a single access network.Such an approach can also negatively impact the core network nodes inthe operator's network, and the network operator may also be required torun a separate Operations Support System (OSS) for the WLAN network andthe cellular network and separate authenticationmechanisms/infrastructure.

As a more specific example in these regards, LTE and 802.11 operate withdifferent paradigms for traffic scheduling. LTE works on the basis of(synchronous) scheduled transmissions over the air while 802.11 works onthe basis of opportunistic (asynchronous) transmission based on channelavailability. There is no mechanism to merge these two paradigms and tothereby integrate the 802.11 and LTE access networks at a low level toenable bearer split across these access networks to enable peakthroughput improvements per application.

As another example in these regards, there are no particular effectiveand efficient communicative protocols by which one can readily establishsimultaneous use of both licensed and unlicensed wireless spectrum.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram in accordance with the disclosure.

FIG. 2 is a block diagram in accordance with the disclosure.

FIG. 3 is an architectural representation in accordance with thedisclosure.

FIG. 4 is an architectural representation in accordance with thedisclosure.

FIG. 5 is a call flow diagram in accordance with the disclosure.

FIG. 6 is a call flow diagram in accordance with the disclosure.

FIG. 7 is a call flow diagram in accordance with the disclosure.

FIG. 8 is a call flow diagram in accordance with the disclosure.

FIG. 9 is a call flow diagram in accordance with the disclosure.

FIG. 10 is an architectural representation in accordance with thedisclosure.

FIG. 11 is an architectural representation in accordance with thedisclosure.

FIG. 12 is an architectural representation in accordance with thedisclosure.

FIG. 13 is an architectural representation in accordance with thedisclosure.

FIG. 14 is an architectural representation in accordance with thedisclosure.

FIG. 15 is a call flow diagram in accordance with the prior art.

FIG. 16 is a call flow diagram in accordance with the prior art.

DETAILED DESCRIPTION

The following describes an apparatus and method pertaining to achievinga tighter integration between 802.11 and LTE below the PDCP or the RLClayer of LTE. This integration includes configuring a control circuit todetermine that a wireless portable electronic device currently beingserviced via licensed wireless spectrum should also be served viaunlicensed wireless spectrum and then transmitting a Radio ResourceControl (RRC) message to cause the wireless portable electronic deviceto connect to a network node operating in the unlicensed wirelessspectrum. By one approach this control circuit comprises an EvolvedNode-B base station in a Long Term Evolution (LTE) Radio Access Network(RAN) and the network node operating in the unlicensed wireless spectrumcomprises an 802.11-compatible wireless local area network node.

So configured, both licensed and unlicensed wireless spectrum can besimultaneously leveraged to support the data transmission/receptionrequirements of a portable electronic device. These teachings arerelatively simple to embody and yet efficient, effective, and reliablein practice.

For simplicity and clarity of illustration, reference numerals may berepeated among the figures to indicate corresponding or analogouselements. Numerous details are set forth to provide an understanding ofthe embodiments described herein. The embodiments may be practicedwithout these details. In other instances, well-known methods,procedures, and components have not been described in detail to avoidobscuring the embodiments described. The description is not to beconsidered as limited to the scope of the embodiments described herein.

The various examples provided here in presume implementation via acorresponding wireless portable electronic device, a network node orentity that employs licensed wireless spectrum, and/or an access pointthat employs unlicensed wireless spectrum. Without intending anyreticular limitations in these regards, FIG. 1 presents some examples inthese regards.

In this example the wireless portable electronic device 100 includes acontrol circuit 101 that operably couples to a memory 102 and one ormore user interfaces 103. Such a control circuit 101 can comprise afixed-purpose hard-wired platform or can comprise a partially or whollyprogrammable platform. These architectural options are well known andunderstood in the art and require no further description here. Thiscontrol circuit 101 is configured (for example, by using correspondingprogramming as will be well understood by those skilled in the art) tocarry out one or more of the steps, actions, and/or functions describedherein.

The memory 102 may be integral to the control circuit 101 or can bephysically discrete (in whole or in part) from the control circuit 101as desired. This memory 102 can also be local with respect to thecontrol circuit 101 (where, for example, both share a common circuitboard, chassis, power supply, and/or housing) or can be partially orwholly remote with respect to the control circuit 101 (where, forexample, the memory 102 is physically located in another facility,metropolitan area, or even country as compared to the control circuit101).

This memory 102 can serve, for example, to non-transitorily store thecomputer instructions that, when executed by the control circuit 101,cause the control circuit 101 to behave as described herein. (As usedherein, this reference to “non-transitorily” will be understood to referto a non-ephemeral state for the stored contents (and hence excludeswhen the stored contents merely constitute signals or waves) rather thanvolatility of the storage media itself and hence includes bothnon-volatile memory (such as read-only memory (ROM) as well as volatilememory (such as an erasable programmable read-only memory (EPROM).)

The user interface 103 can comprise any of a variety of user-inputmechanisms (such as, but not limited to, keyboards and keypads,cursor-control devices, touch-sensitive displays, speech-recognitioninterfaces, gesture-recognition interfaces, and so forth) and/oruser-output mechanisms (such as, but not limited to, visual displays,audio transducers, printers, and so forth) to facilitate receivinginformation and/or instructions from a user and/or providing informationto a user.

In this illustrative example the control circuit 101 also operablycouples to a first transceiver comprising a Long Term Evolution(LTE)-compatible wireless transceiver 105 that employs licensed wirelessspectrum. The control circuit 101 also operably couples to a secondtransceiver comprising an unlicensed wireless spectrum transceiver 106such as an 802.11-compatible transceiver. Such transceivers are verywell known in the art and therefore, for the sake of brevity, furtherelaboration will not be provided here.

So configured, the wireless portable electronic device 100 cancommunicate via the LTE-compatible wireless transceiver 105 with acorresponding LTE base station 107 (such as an Evolved Node-B basestation in an LTE Radio Access Network (RAN). The wireless portableelectronic device 100 can also communicate, via the unlicensed wirelessspectrum transceiver 106, with a corresponding WLAN access point 108such as a Wi-Fi access point. In this illustrative example theaforementioned LTE base station 107 communicatively couples to the WLANaccess point 108. This communicative coupling can comprise a wirelessand/or a wired coupling as desired.

As a further illustrative example in these regards, but again withoutintending any particular limitations by way of the specificity of thisexample, FIG. 2 presents an exemplary portable electronic device 100that includes the aforementioned control circuit 101 that controls theoverall operation of the portable electronic device 100. The portableelectronic device also includes an operating system 246 and softwareprograms, applications, or components 248 that are executed by thecontrol circuit 101 and that are typically stored in the aforementionedmemory 102.

At least some wireless communication functions, including data and voicecommunications, are performed through the aforementioned firsttransceiver 105 and second transceiver 106. The first transceiver 105communicates via a corresponding network 250 (and in particular via theaforementioned LTE base station 107) while the second transceiver 106communicates via the aforementioned WLAN access point 108 (not shown inFIG. 2).

A power source 242, such as one or more rechargeable batteries or a portto an external power supply, powers the device. The control circuit 101may interact with an accelerometer 236 that may be utilized to detectdirection of gravitational forces or gravity-induced reaction forces.The control circuit 101 also interacts with a variety of othercomponents, such as a Random Access Memory (RAM) 208, an auxiliaryinput/output (I/O) subsystem 224, a data port 226, a speaker 228, amicrophone 230, and other device subsystems 234 of choice.

The aforementioned user interface 103 can include a display 212 that isdisposed in conjunction with a touch-sensitive overlay 214 that operablycouples to an electronic controller 216. Together these components cancomprise a touch-sensitive display that serves as a graphical-userinterface. Information, such as text, characters, symbols, images,icons, and other items may be displayed on the touch-sensitive displayvia the control circuit 101.

For the sake of an illustrative example the following description willpresume that the aforementioned network 250 comprises an LTE RAN (RadioAccess Network) that consists of eNBs to provide the LTE user plane(PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towardsthe UE. The eNBs are interconnected with each other by means of an X2interface. The eNBs are also connected by means of an S1 interface tothe EPC (Evolved Packet Core), more specifically to an MME (MobilityManagement Entity) by means of an S1-MME interface and to a ServingGateway (S-GW) by means of an S1-U interface. The S1 interface supportsa many-to-many relation between MMEs/Serving Gateways and eNBs.

PDCP, RLC, and MAC sublayers (terminated in eNB on the network side)perform functions including header compression (PDCP), ciphering (PDCP),scheduling (MAC), ARQ (RLC), and HARQ (MAC) for the user plane (UP). TheRRC protocol mainly controls the mobility procedures and systembroadcast messages and so forth.

In LTE, transmission on the medium happens under control of the MACprotocol layer via scheduling. Downlink packets are buffered in the eNBand a scheduler in the eNB's MAC layer determines when packets will betransmitted to a given UE. In the uplink each UE has to requestresources for the uplink transmission and an uplink scheduler within theeNB's MAC layer decides which UE will be allowed access to the uplinkchannel resources in any given Transmission Time Interval (TTI).

The MAC layer interfaces with the RLC layer above by grabbing a givenamount of data from the RLC layer at each transmission opportunity. Theamount of data obtained by the MAC layer from the RLC layer depends onthe amount of data that can be accommodated on a given TTI. This amountof data (or the data size) indicated by MAC to the higher layers at eachTTI is referred to as the grant size. This grant size is explicitlycommunicated by the eNB to the UE for both downlink and uplink grantsvia the downlink PDCCH channel. Thus, conveying the grant size to upperlayers is one of the services provided by MAC to RLC for both uplink anddownlink in case of LTE.

Since the eNB is responsible for providing the grants for uplink datatransmissions, the eNB needs to have an idea of how much pending datathere is in the UE's uplink buffer. Accordingly, when the data in theUE's uplink buffer changes (for example, when new data arrives in thePDCP layer), the UE generates a buffer status report (BSR) to inform theeNB of the pending uplink data in the UE's buffer upon certain triggerconditions (see, for example, 3GPP TS 36.321). If no uplink resourcesare available to the UE to send the BSR, the UE must first send aninitial short “scheduling request” indication to the eNB and await thesubsequent grant of uplink resources on which to send the BSRinformation. Having received the BSR, the eNB then takes the UE's bufferstatus into account in its scheduling decisions and subsequent uplinkgrants.

Once the MAC obtains a given chunk of data from the RLC layer, the MACpackages the data into a MAC PDU and submits to the lower layers (inthis case, the physical layer) for transmission. A single MAC PDU formsone transport block (one transport block is transmitted per TTI, i.e.per 1 ms). The MAC PDU may carry multiple MAC SDUs (i.e. multiple RLCPDUs). In this way the MAC layer can potentially multiplex traffic frommultiple RLC logical channels into one MAC PDU.

There is a MAC sub-header associated with each MAC SDU. Thesesub-headers are used to inform the receiving MAC entity as to how manySDUs there are and with which logical channels those SDUs areassociated. A transport format is associated with each transport blockthat informs the receiving entity of the MCS scheme that has been usedin the PHY transmission of the transport block.

The MAC layer may add padding bits to the MAC PDU so that it fits in theTTI (in the case where the grant size is greater than the available sizeof the MAC PDU). The LTE MAC always informs the higher layers about eachtransmission opportunity (grant) for a given TTI. Hence, LTE MACoperation can be seen as being synchronous (in particular, they occur at1 ms intervals—which is also the TTI in case of LTE). In other words,every 1 ms, when there is a transmission opportunity, the LTE MACinforms the higher layers of this opportunity.

The MAC also provides a mechanism to retransmit a MAC PDU. That is, oncethe MAC PDU is submitted to the lower layers, the MAC layer provides aHybrid Automatic Repeat Request (HARQ) service to ensure delivery ofdata between the peer MAC entities.

The RLC layer in LTE is mainly responsible for segmentation andconcatenation of the higher layer (PDCP) data packets. RLC plays theimportant role of feeding the lower layer (MAC) with just enough datathat can be transmitted using a given transmission opportunity (i.e., ascheduled TTI). The amount of data that can be sent via a giventransmission opportunity is variable and is a function of current radioconditions and scheduling decisions amongst other things.

The RLC layer operates in 3 modes as follows. In an RLC transparent mode(TM), no segmentation or concatenation of upper layer (PDCP) data ispossible, an RLC header is not appended to the data, and higher layerdata is passed transparently (unaltered) to the MAC. RLC TM is typicallyused where the size of the data whose scheduling instances and scheduledsize is known a priori (hence obviating the need for segmentation orconcatenation). A typical example of RLC TM data is broadcast controlchannel (BCCH) data that is periodically repeated in downlink atpredetermined time intervals.

In an RLC Unacknowledged Mode (UM), segmentation or concatenation ispossible and RLC SDU (PDCP data) is segmented and/or concatenated tocreate one or more RLC PDUs that are passed down to the MAC. Thesegmentation or concatenation is performed based on the grant sizeindicated by the MAC layer. An RLC header is appended and there is noacknowledgement of the received RLC data from the peer entity. RLC UM istypically used for applications that are delay sensitive and errortolerant. The lower layers (i.e., the MAC layer and physical layer)below the RLC layer combine to provide an ultimately unreliable channel.Hence, without RLC acknowledgements, there may be residual errors in thetransmitted data packets. Some applications (like voice and interactivevideo) are tolerant to residual errors in the received bit stream butare delay sensitive. RLC UM is typically used for such applications.

In an RLC Acknowledged Mode (AM), segmentation and/or concatenation isagain possible and hence the initial aspects of the RLC UnacknowledgedMode are utilized here. After then appending an RLC header thetransmitter entity buffers the transmitted RLC PDUs and awaits anACK/NACK from the receiver RLC entity. Upon receiving a NACK, the RLCPDU is retransmitted (after further segmentation if necessary dependingon the grant size for retransmission instance). RLC AM is used forapplications that essentially rely on reliable delivery (as a furthercomplement to HARQ at the MAC layer which already provides somerobustness against transmission errors). Applications such as HTTP, filedownload, and so forth would typically use an RLC AM radio bearer.

In LTE the UE may be either in RRC_CONNECTED (connected) mode or inRRC_IDLE (idle) mode. The mechanisms used to control UE mobility betweencells of the network differs between the idle and connected modes. Inidle mode, mobility is controlled by the UE. In particular, the UEperforms cell selection and reselection procedures as per 3GPP TechnicalSpecification 36.304 and in accordance with related configurationparameters set by the network. Following selection or reselection of anew cell by the UE, the UE will inform the network of its new locationonly if the new cell belongs to a tracking area that is different fromthe tracking area of the previous camped cell (a tracking area is agroup of cells—which cells belong to which tracking area is dependentupon network configuration). Thus, in idle mode, mobility reports areonly seldom sent by the UE, and the network is aware of the UE'slocation with relatively coarse granularity (tracking area level asopposed to cell level).

In connected mode, the UE performs measurements of other cells (on thesame or other frequencies) according to the configuration sent to the UEby the network in measurement control messages. The measurements arereported by the UE to the network wherein they are used by the networkto make handover decisions. Subsequent to a handover decision by thenetwork, the UE is instructed to move to another cell or frequency.Thus, in connected mode, measurement reports may be sent relativelyfrequently and the network is aware of the UE's location with finergranularity (to the cell level).

Aspects of particular note in the foregoing regards include the UE beingis requested to make measurements on other eNBs, the UE providing theeNB with its measurements, and the eNB making the decision as to whetheror not the device will handover to the new eNB. At inter eNB handover ofthe Primary Cell (PCell) the eNB can use RRC signalling to add/remove orreconfigure Secondary Cells (SCells). SCells are deactivated athandover.

Carrier aggregation (CA) is a feature that enables two or more LTEcarriers (called component carriers—CCs) to be simultaneously used tosend data to/from the same UE. LTE allows carrier aggregation for up to5 CCs at the same time. Accordingly a UE may be configured with onePCell and one or more SCells. LTE provides a MAC layer mechanism foractivating/deactivating an SCell that is used in carrier aggregation.MAC layer Control Elements can be transmitted by an eNB to activate ordeactivate SCells that have been previously configured in a UE via RRCsignalling. The MAC control elements contain a bitmap for all configuredSCells to indicate which are activated or deactivated.

The eNB can configure the device to make measurements on SCells and toproduce measurement reports when certain criteria are satisfied.Examples in these regards include when an SCell signal becomes worsethan a signal threshold or when an SCell signal becomes greater than athreshold. The eNB can then add or remove SCells using theRRCconnectionreconfiguration message. FIG. 15 presents an illustrativeconnection set-up procedure 1500 in these particular regards.

An LTE UE establishes Internet Protocol (IP) connectivity with theEvolved Packet Core (EPC) using the ATTACH procedure. Accordingly thedevice has to have performed a PLMN selection and a cell selection forthe purposes of deciding which eNB to send the Attach Request and aNon-Access Stratum (NAS) Security Mode Command procedure is used toestablish a NAS security association between the UE and the MobilityManagement Entity (MME) in the EPC (encryption/integrity protection) toprotect NAS signalling. In addition the access stratum Security ModeCommand procedure is used to enable ciphering of user plane traffic andboth ciphering and integrity protection of control plane RRC traffic.Also, the P-GW assigns an IP address for a default bearer and this isnotified to the UE.

In LTE, PDCP provides ciphering/deciphering (between the UE and the eNB)for both the user plane and the RRC control plane, while providingintegrity protection and verification for the LTE RRC control planeonly. LTE specifies a hierarchy of keys to support this approach. Oneparticularly important key is the KUPenc key which is the key thatprovides for user plane ciphering. This particular key is derived viaKeNB, which is derived via KASME, which is derived via the CK and IK,which are derived from the subscriber specific Master key K. In derivinga new KeNB key during handover, input parameters corresponding to thephysical cell ID, Nex Hop (NH), and downlink frequency (EARFCN-DL) areused.

One commonly implemented method of accessing the channel implemented inIEEE 802.11 MAC is termed the Distributed Coordination Function (DCF)which is a CSMA/CA method. The concept of Inter Frame Spacing (IFS) iskey to the method by which stations access the channel in 802.11. Once aprevious transmission on the channel has completed, a station will waitfor at least an interframe spacing period before starting or resumingits own backoff timer.

There are multiple IFS defined, which enables priority handling to beachieved in accessing the channel. SIFS (Short IFS) is the shortest IFSand is used by higher priority transmissions such as CTS/ACKtransmissions. These transmissions can occur immediately after the SIFShas elapsed. Stations can access the channel on a contention basis afterthe DCF-IFS (DIFS) has expired. SIFS is of the order of 10 μs and DIFSis of the order of 50 μs (values vary between 802.11 physical layers).

As regards contending for channel access, stations monitor the channelfor the channel to go quiet. The device waits for the aforementionedDIFS period and it is then necessary for the channel to remain quiet foran additional Backoff period before the station can access the channel.Backoff is a randomly-drawn time delay parameter. In order to ensurethat the device is eventually able to access the channel the Backoffperiod is decremented after every interval that the channel is quiet fora period DIFS. The duration of the Backoff timer is randomly determinedbased on the CWindow (contention window). The CW increases after anunsuccessful transmission and reverts to CWmin after a successfultransmission.

802.11 also defines a Point Coordination Function (PCF) that is used inan access point within an infrastructure BSS. The point coordinatordetermines which station currently has the right to transmit so thatcontention is avoided in this mode. (That said, this mode of operationhas not been widely implemented/deployed in practice.)

Generally speaking, 802.11 MAC is based on opportunistic transmission ofdata on the physical layer (i.e., transmitting when the medium is free).Once the MAC gains access to the medium, it transmits until the MAC PDUis completely transmitted. Once transmission of MAC PDU is complete, the802.11 MAC grabs another chunk of data (usually an IP packet) from theupper layers and awaits another transmission opportunity. Thus, the802.11 MAC can be viewed as operating in an asynchronous mode—i.e.accessing and grabbing data from the higher layers whenever thetransmission (and acknowledgement) of a previous packet concludes. Suchan approach contrasts with LTE practice where the LTE MAC operates on 1ms time boundaries.

Generally speaking, mobility in case of 802.11 is UE controlled. The UEmeasures the signal strength of available 802.11 access points andselects the most suitable one according to implementation-specificcriteria and associates with the selected access point forcommunication. If the UE moves and hence in the process loses connectionto its associated 802.11 access point, it reinitiates a search foravailable 802.11 access points and again selects the best availableaccess point. The UE may perform this UE-based mobility procedurewithout regard to whether or not the UE is also then actively engaged inuser data transfer.

Referring generally to FIG. 16, the process 1600 of obtainingconnectivity over a conventional 802.11-based WLAN involves a number ofsteps that are undertaken as follows. First, scanning determines whichWLANs are within range. There are two main approaches in these regards.With passive scanning the device tunes to different radio channels andlistens for 802.11 Beacon frames. By default, beacon frames aretypically transmitted every 100 msec. With active scanning, when thedevice needs to make a selection quickly (and does not wish to wait forthe periodic beacon transmission) the UE can issue a Probe Requestmessage. Access Points that receive the Probe request message willrespond with a Probe Response. Once the device knows which WLANs arewithin coverage and their characteristics (e.g. signal strength, thetype of credentials the WLAN will accept) it can choose a WLAN.

802.11 supports two types of authentication. With Open SystemAuthentication any device may connect to the network without requiringan exchange of credentials. A two-step message exchange between thedevice and the access point completes the authentication. With SharedKey Authentication (WEP), manually-configured keys in the access pointand the device are used as part of a four-step message exchange betweenthe device and the access point. (This mechanism is now largelydiscredited.)

After successful MAC layer authentication the device needs to associatewith the access point. Association serves a number of purposes. Anaccess point may form part of an Extended Service Set (ESS). Accesspoints's within an ESS are connected to one another (typically via awired connection). The association process enables the device toindicate the particular access point within the ESS with which it wishesto communicate. This then enables the access point to notify thedistribution system frame router so that downlink packets are sent tothe appropriate access point for downlink transmission. Association alsofacilitates the sharing of the capabilities (such as PHY layercapabilities) of the device and access point.

Given the problems with open system authentication and shared key WEPauthentication, it is expected that a carrier WLAN deployment might makeuse of 802.1X (EAPoL) authentication mechanisms. Such mechanisms areused as part of WPA and WPA2 (Wi-Fi Protected Access). 802.1X, incombination with a suitable EAP method (e.g. EAP-SIM), allows the deviceto authenticate using its cellular SIM credentials (amongst other e.g.certificate based solutions).

Where 802.1X is used the access point performs port blocking until afterthe authentication process is complete. In other words the access pointallows the device to send EAP frames that are passed to theauthentication server but the device is prevented from sending othertypes of traffic. The procedure also delivers keys that are used for802.11 MAC layer encryption.

Once authenticated the device can acquire an IP address using DHCP. Thedevice can then send and receive IP packets via corresponding user planeIP connectivity.

802.11 provides a number of mechanisms for encrypting andintegrity-protecting traffic, these include WEP, TKIP and CCMP. WEP isincreasingly distrusted] and TKIP is being phased out in the market.TKIP was used in WPA and the AES-based CCMP is used as part of WPA2.CCMP is considered by many to be the most robust approach. Morerecently, 802.11 provides a Protected Management Frames feature (IEEE802.11w-2009) that provides for encryption and integrity protection ofWLAN management frames. This feature makes use of existing mechanisms,e.g. CCMP.

IEEE 802.1AC is an architecture document that describes a MAC interface.Historically all the IEEE 802 groups (802.3, 802.5, 802.11, 802.17,802.20) have developed slightly different definitions of their MACinterface for various reasons. In IEEE 802.1AC a network-agnosticdefinition of a MAC is described. The MAC SAP (service access point)defined in IEEE 802.1AC provides a standard set of services to the layerabove (MAC Service user).

IEEE 802.11ak is an ongoing effort in 802.11 to bring the 802.11standard in line with the IEEE 802.1AC definition of the common MAC SAP.This provides a defined interface on the STA and AP for MAC frames to betransported transparently across an 802.11 network.

In order to enable operators of 3GPP systems to use unlicensed spectrum,3GPP has defined mechanisms for LTE and 802.11 interworking. Thesemechanisms enable a device to connect to the EPC using either LTE orWLAN access technologies. In recent enhancements to this interworkingapproach (as part of 3GPP Release-12), choice-of-access technology isbased on additional radio-level information (such as signal strength,quality, and system load) and is governed either by rules provided tothe UE via the RAN (RAN rules) or by rules provided to the UE via theEPC in ANDSF policies.

There are a range of different methods provided in 3GPP release 12 (andprevious releases) by which 3GPP operators can provide connectivity overa WLAN into the 3GPP operator's CN. All these methods are distinguishedby the fact that the mobility anchor point is the P-GW in the EPC corenetwork. In this way handover between the WLAN and cellular-basedservice is supported while maintaining the UE's IP address (IP sessioncontinuity). The network can use either network-based IP mobility orhost-based IP mobility to manage UE mobility. In the former case thedevice is assigned an IP address and the network ensures that packetsdestined for the user reach the user as the device moves around (e.g. byre-routing GTP tunnels). In host-based IP mobility the device receives anew IP address when it changes to a new WLAN and needs to notify the3GPP CN P-GW (home agent) of the new IP address so that packets destinedfor the user can be appropriately re-routed to the new IP address.

The present teachings present various approaches to achieving a tighterintegration between 802.11 and LTE below the PDCP or the RLC layer ofLTE. This model of interworking between LTE and 802.11 is sometimesreferred to herein as Tight Coupled Inter-Working (TCIW). FIG. 3presents a general protocol architecture 300 in these regards. (Notethat the 802.2 LLC layer may or may not be present; also note that theportable electronic device 100 may sometimes be referred to herein asUser Equipment (UE) in keeping with industry parlance.)

Unlike LTE-U the present teachings propose re-using existing mechanismsin 802.11 MAC and Phy. The TCIW mode of operation is only exposed to theeNB (as the protocol stacks are merged below PDCP layer—i.e., theprotocol stack in the eNB), it is hence transparent to the Non-AccessStratum. Thus, the MME or SGW in the EPC are unaware of the TCIWoperation. This also means that no new core network nodes are necessaryto support the TCIW operation.

By one approach the 802.11 SCell shown in FIG. 3 may belong to one ofthe access points of an ESS controlled by the eNB when link layermobility of 802.11 can be used for the UE to seamlessly (i.e., withoutinvolving the eNB) move between the access points belonging to the sameESS—in this scenario, the ESS is identified by a HESSID.

In the more likely case of the SCell being a single access point underthe control of the eNB, the HESSID and the BSSID of the 802.11 SCellessentially identify the same SCell node. The SCell is generallydescribed herein as being identified by its BSSID. This also means thatan unlicensed carrier is used as an aggregated carrier along with thelicensed carrier which is the LTE PCell (i.e. CA mode of operation ofLTE). In the general case however, the concepts described herein mayalso be extended to a WLAN architecture where multiple access points arecontrolled by the eNB and these access points form an ESS identified bya HESSID (instead of BSSID).

By one approach the 802.11 access point is logically integrated into theeNB. Accordingly, the Destination Address (DA) that indicates the finaldestination of the MAC frames on the 802.11 air interface can be set toanything indicating that the MAC data frames sent on 802.11 need to berouted to the eNB (this could be, for example, the MAC address of theeNB or even the PGW/SGW address in the operator core network). Uponreaching the eNB's RLC entity they are reassembled and passed on to theupper layers. Similarly, in downlink, the received MAC frames on the802.11 air interface are also routed to the receiving RLC entity on theUE side for further processing.

FIG. 4 presents one illustrative example of network architecture 400 fordeploying the TCIW solutions disclosed herein. In particular, thepresent teachings propose using an 802.11 based channel operating inunlicensed spectrum as a secondary cell/carrier (SCell over the airinterface) which is terminated in an LTE eNB. Following the existing LTEcarrier aggregation terminology, the air interface between the eNB andthe UE over the licensed carrier (i.e., LTE) is referred to as the LTEPCell and the air interface between the eNB and the UE over anunlicensed carrier (i.e., 802.11) is referred to as the 802.11 SCell.

As well exemplified in FIG. 4 the user plane traffic 401 can be splitbetween the LTE PCell 402 and the 802.11 SCell 403 whilst the LTE PCell402 acts as a mobility anchor (such that the core network knows the UElocation based on the connection to the LTE PCell). This architectureminimizes negative impacts to the 802.11 side and maximizes the reuse ofthe protocol messages (especially the RRC messages) on the LTE side to avery considerable extent.

In order for the 802.11 SCell to be used for data transfer, the 802.11SCell is first added and then activated (following the terminology ofLTE). By one approach the eNB is responsible for both the addition andremoval of the SCell and also activation and deactivation thereof.Accordingly, by one approach the eNB makes the decisions to add/deleteor modify the 802.11 SCell for a given UE. Such a decision can be basedon any of a variety of factors (and any of a variety of combinations ofsuch factors. Examples in these regards include but are not limited to,the volume of data, radio quality, Pcell and Scell loading, UE activebearers, subscription-related data, channel conditions, and mobilitystatus. Further details regarding these factors are as follows.

Volume of data: The addition of an SCell will often be more appropriatefor UE's that are generating large volumes of data. An eNB can know(based, for example, on history or subscription data) that a given UE islikely to generate large volumes of data either in UL or DL. In such acase the eNB can enable the 802.11 SCell when the UE has generated orconsumed a high volume of data (that exceeds, for example, apredetermined threshold of data volume in a predetermined period of timeor when the mean data rate measured over a predetermined period of timeexceeds a given threshold).

Radio quality: Based upon the radio quality (as indicated, for example,by RSNI/RCPI as reported from the UE) the eNB can add the SCell whenquality is good and remove the SCell when radio quality is bad.

Pcell and Scell loading: As one example, the eNB can add an SCell whenthe load on the PCell is above a first threshold and similarly canremove an SCell when the loading becomes lower than a correspondingsecond threshold (which may be the same as, or different than, the firstthreshold). As another example, the eNB can add an SCell when the loadon SCell is below a threshold and refrain from adding an SCell when theload on SCell is above the threshold. As yet another example, when theresources on the LTE PCell are scarce (perhaps due to large number ofUEs or a large number of data hungry UEs in the system) then the eNB maychoose to enable an 802.11 SCell for applicable UEs.

UE active bearers: Active bearers that require high data rates (forexample, particular data bearers that are known to be resource hungrywhen associated with high bandwidth applications) can prompt theaddition/enabling of an 802.11 SCell. By one approach the type oftraffic data and/or knowledge of running applications (and/or theirstatus) can be mapped to active bearers and their respective toleranceto delay can further inform the addition/enabling and/or deletion ofSCells by the eNB. By another approach the possible data rate over the802.11 leg (as estimated by eNB based, for instance, on some assistancedata from the UE) can inform this decision. Parameters such as RCPI andRSNI and/or 802.11 MCS scheme could be indicated by the UE to the eNB tofacilitate this decision.

Subscription-related data: TCIW may be provisioned by the operators as avalue-added service only to some customers and whether the 802.11 SCellis enabled or not may be based on such subscription data. For example,when the subscription data of the UE indicates a preference to use an802.11 air interface when available, the eNB may decide to add (or tomaintain) an 802.11 SCell based on that preference.

Channel conditions: The eNB can be configured to decide to add the802.11 SCell to the UE experience if a channel condition measurementindicates a suitably strong 802.11 SCell or that the UE is associatedwith the 802.11 SCell (presuming, for example, a UE-controlled optionfor association). Conversely, if the measurement results indicate thatthe received signal strength/quality/load of the 802.11 SCell is poor(presuming a network-controlled addition option) or that the UE isdisassociated with the 802.11 SCell (presuming a UE-controlled option)then the eNB may remove the 802.11 SCell for this UE.

Mobility status: For high mobility UEs, adding 802.11 SCells may not beappropriate as the UEs are likely to move from one SCell to another at ahigh rate and thus generate a lot of mobility-related signaling. This isespecially of concern because the 802.11 SCell coverage zones are likelyto be small in size and hence high mobility UEs are likely to move inand out of coverage at a rapid rate. Thus, an eNB may refrain fromadding 802.11 SCells for high mobility UEs or remove an 802.11 SCellupon detecting an increased mobility rate where, for example, UE speedis beyond a predetermined threshold or the number of cell changes over apredetermined time exceeds a threshold rate. Conversely, for lowmobility UEs, the eNB may add 802.11 SCells.

Activating an SCell enables the user plane over that Scell. The eNB maydecide to activate the SCell based on one or a combination of factors. Anon-exhaustive listing of possibly useful examples in these regardsinclude:

-   -   When the data volume in downlink or uplink exceeds a threshold;    -   When the QoS requirements of the data (regarding, for example,        data rate, latency, reliability) are deemed to be met using the        802.11 air interface;    -   When the load on the LTE PCell exceeds a threshold;    -   When the signal level, signal quality, load, and/or medium        utilization factor on the 802.11 air interface falls below a        threshold;    -   When the subscription data of the UE indicates a preference to        use an 802.11 air interface when available;    -   When the UE indicates a preference to allow 3GPP usage of its        available 802.11 hardware or processing resources;    -   When an LTE PCell RF level drops below a threshold.

Similarly, the eNB may decide to deactivate the SCell based on one or acombination of such factors as:

-   -   When the data volume in the downlink or uplink falls below a        threshold;    -   When the QoS requirements of the data (regarding, for example,        data rate, latency, and so forth) are deemed to be not met using        the 802.11 air interface;    -   When the load on the LTE PCell falls below a threshold;    -   When the signal level, signal quality, load, and/or medium        utilization factor on the 802.11 air interface exceeds a        threshold;    -   When the subscription data of the UE indicates a preference to        use an LTE air interface;    -   When the UE indicates a preference to disallow 3GPP usage of its        available 802.11 hardware or processing resources;    -   When an 802.11 SCell RF level drops below a threshold.

By one approach these teachings employ a network-centric LTE-basedmechanism to add/modify/delete an SCell operating in unlicensed spectrumvia modifications made to the 802.11 procedures in order to fit in withthe network-controlled LTE paradigm. As one illustrative example inthese regards, the UE attaches to the cellular network and the(licensed) PCell using existing procedures. As part of this process thedevice is authenticated and is provided with an IP address/PDNconnection for a default bearer. The device provides its capabilityinformation (including 802.11 capability) as part of the attachprocedure.

When the eNB decides that it would be useful (or might in the future beuseful) to add an unlicensed band SCell, the eNB uses RRC signaling(such as the RRCConnectionRecofiguration/measConfig message) toconfigure the device with the WLAN identifier such as the BSSID, ISMband(s), and channel(s) of the 802.11 SCell(s) for which the deviceshould provide measurement reports. The eNB can also provide anythresholds for the measured metrics (such as thresholds for 802.11 radiosignal strength or quality such as RCPI/RSNI metrics or any desiredthroughput estimate thresholds or the like) which the device should usefor triggering the measurement reports.

Measurement metrics may be any metric that would reliably indicate theradio quality or signal strength. For instance this could be thosemetrics that are specified in 802.11, such as RCPI and RSNI.Measurements indicating estimated throughput on the WLAN AP may also bereported. Metrics such as channel utilization may also be included ifdesired.

The device would make measurements (for instance on the 802.11 beacons)of the provided WLAN and would report measurements to the eNB using RRCsignaling when the measurement criteria are met (for example, when agiven metric exceeds a threshold level).

Existing 802.11 passive or active scanning may be used to determinewhether an access point belonging to a provided BSSID is in coverage andto determine the signal level/signal quality/current medium load orutilization level. These procedures may also be optimized using theinformation provided to the UE in the RRC measConfig signalling (e.g.band/channel number of interest). The measurement results can bereported by sending a MeasurementReport message containing themeasurement results for the provided 802.11 BSSID.

The eNB may also receive certain parameters like the “AvailableAdmission Capacity”, “Station Count”, and so forth from the 802.11access point associated with the eNB for TCIW operation. These internalmetrics may be passed on from the access point to the eNB via aninternal interface.

Based on the received measurements from the UE and any informationreceived on the internal interface between the 802.11 access point alongwith any other criteria of interest mentioned herein, an eNB may decideto add an 802.11 SCell for the UE. The eNB can inform the device usingRRC signaling (such as the RRCConnectionReconfiguration message)regarding whether the 802.11 SCell is to be added/deleted/modified.

Depending on information included in the RRCConnectionReconfigurationmessage, there are at least two further options regarding how the UE mayproceed further with attaching to the 802.11 network. Referringgenerally to the process 500 presented in FIG. 5, a first option issimilar to the current LTE handover procedures where the eNB provides ahandover command to the UE in which the target cell radio interfaceaspects are embedded. RRCConnectionReconfiguration is used for thispurpose and this message provides all the relevant 802.11 access pointcapabilities and parameters to enable the UE to enter a state equivalentof the UE 802.11 State 3. For example, the RRCConnectionReconfigurationmessage tunnels the Association Response message that contains thenecessary information for the UE to associate with the 802.11 accesspoint. This approach presumes that the UE's access capabilities on the802.11 side are known to the 802.11 access point.

The network receives the UE's 802.11 capabilities (e.g. included in theUE Radio Access Capabilities message exchanged during the LTE attachprocedure or as sent by the UE in the RRC Connection Reconfigurationcomplete message) and these are passed to the 802.11 access pointthrough an eNB internal interface as shown in FIG. 5. Once the RRCConnection Reconfiguration procedure is complete (i.e. upon reception ofthe RRCConnectionReconfiguration complete message), the eNB may activatethe 802.11 SCell thus enabling user plane data transfer over the 802.11interface (and allowing the UE to move to a state equivalent of the802.11 state 4). Activating the SCell may be achieved using MACsignaling.

Referring generally to the process 600 presented in FIG. 6, pursuant toa second optional approach the RRCConnectionReconfiguration message onlyprovides an active trigger (or command) for the UE to associate with the802.11 AP. Along with the trigger or command, the message may alsoinclude information such as the BSSID of the access point to which theUE is to associate. In this case, the UE enters a state equivalent tothe 802.11 state 2 and initiates the 802.11 Association procedure asshown in FIG. 6. In this particular case, in moving from a stateequivalent to the 802.11 state 2 to state 3 there is no explicit 802.1Xauthentication procedure. This is because, once authenticated on the3GPP network (during the network attach procedure), a UE capable of TCIWoperation is also pre-authenticated for TCIW operation.

In both options described above, the network expects the UE to associatewith the 802.11 SCell upon receiving the RRCConnectionReconfigurationmessage that indicates addition of SCell. These teachings will alsoaccommodate the eNB adding the 802.11 SCell for uplink and/or downlinkoperation.

The UE, however, may in some cases be unable to associate with the802.11 SCell as indicated in the RRCConnectionReconfiguration message(for example, the 802.11 hardware might be currently used for otherpurposes). The UE may also refrain from sending measurement reports thatwould trigger addition of an 802.11 SCell as long as it is unable toassociate with the SCell. However, after receiving theRRCConnectionReconfiguration message instructing the UE to associatewith a given 802.11 message, if the UE is unable to associate with the802.11 SCell, the UE may, for example, execute actions uponReconfiguration failure as specified in 3GPP TS 36.331 section 5.3.5.5.Or, as another example, the UE may send an RRC message to indicate tothe network that the addition of the SCell cannot be complied with asillustrated via the process 700 presented in FIG. 7. A new RRC message(RRCConnectionReconfigurationReject containing the failurecause—indicating inability to associate with the 802.11 SCell) mightserve well when employing this approach.

After associating itself with the 802.11 network, the device canacknowledge the reconfiguration message using theRRCConnectionReconfigurationComplete message and then move to a stateequivalent to the 802.11 state 3. By one approach the device will havesupplied the eNB with an identifier to identify the device on the 802.11SCell (for instance the MAC address of the UE), so that the interprotocol layer (bearer) bindings can be put in place. The 802.11 MACaddress could be provided by the UE in theRRCConnectionReconfigurationComplete message or could have been providedearlier (for example, during cellular network attachment along with RRCcapability exchange signaling).

Further, once the RRC Connection Reconfiguration procedure is complete(i.e. upon reception of the RRCConnectionReconfiguration completemessage), the eNB may activate the 802.11 SCell thus enabling user planedata transfer over the 802.11 interface (and allowing the UE to move toa state equivalent to the 802.11 state 4). Activating the SCell may beachieved using MAC signaling.

It is also worth highlighting that compared to the normal way ofobtaining IP connectivity over an 802.11 network, signaling associatedwith 802.11-based authentication (open authentication or WEP) or802.1X-based authentication does not need to be used. Note also that theUE already has an IP address as provided by the PGW. Hence, the UE doesnot need an IP address specific to the wireless LAN interface (and hencedoes not need to perform any DHCP procedure). However, it may beadvantageous from an implementation perspective to include the IPprotocol (and possibly UDP as well), terminated below the LTE RLC layer,for example, to align the behavior for TCIW UEs with those using legacyWiFi at the same device.

As an alternative to the foregoing, and referring to the process 800generally shown in FIG. 8, selection of the 802.11 network selection canbe left to the UE. In this case the UE associates with an 802.11 SCellcontrolled by the eNB. Assistance information pertaining to the 802.11SCell that is controlled by the eNB may be conveyed to the UE (eithervia dedicated signaling, a system information broadcast, or viapre-configuration in the UE). This assistance information may includedetails such as the BSSID (802.11 MAC address) of the 802.11 SCell ofeNB and/or other information useful in measuring/associating with theSCell (such as, for example, RF Band and channel details of the 802.11SCell controlled by the eNB).

As regards the aforementioned assistance information pertaining to theBSSID, this information can be provided either explicitly via aninformation element or derived implicitly by the UE based on apreconfigured relation (for example, by employing a known lookup tableshowing a relation between the Cell ID and 802.11 BSSID associated withthe SCell) between the system information such as the PLMN or the cellID of the LTE PCell. Other identifiers indicating an association of802.11 SCells with a particular eNB may also be used, such as SSID orHESSID, in which case seamless link layer mobility within the accesspoints belonging to the same SSID/HESSID would be possible.

After obtaining the details of the 802.11 access point associated withthe eNB, the UE can associate with the 802.11 access point based oncertain trigger criteria. One example in these regards includes thedevice associating with the 802.11 SCell at the earliest opportunity andin advance of the SCell actually being needed (the details of the 802.11SCell to which the UE may associate with may be obtained either viabroadcast signaling or dedicated RRC signaling). This approach can beuseful to avoid a delay in associating at a time of need. Further, bypre-associating with the 802.11 SCell, the UE may also ensure that the802.11 hardware resources (Wi-Fi chip hardware, firmware, or otherprocessing capability) are used for connecting with the 802.11 SCellinstead of connecting to another non-3GPP operator-controlled WLAN (asconnecting to another non-3GPP WLAN might delay the SCell addition).

When the device cannot use its 802.11 hardware for associating with the802.11 SCell controlled by the eNB, the device may refrain fromassociating. The device may not be in a position to associate with the802.11 access point controlled by the eNB, for instance, if the 802.11hardware is currently being used for other purposes like the UE beingassociated with another non-operator controlled 802.11 access point orthe UE is engaged in a Miracast session or a Wi-Fi direct session. Oncethe device hardware becomes available for the 802.11 SCell controlled bythe eNB, the device may then associate with the SCell.

Once the UE is associated with the 802.11 SCell, the UE enters a stateequivalent to the 802.11 state 3. User plane data transfer is not yetpossible on the 802.11 link. Similar to the network-controlled SCelladdition described herein, the UE need not perform the explicit steps of802.11 authentication (i.e. neither the 802.11 authentication nor the802.1X authentication procedures are executed). The UE ispre-authenticated from an 802.11 perspective and hence the UE does nothave to perform any further authentication procedures specific to 802.11access.

The eNB is then made aware of the fact that the UE has successfullyassociated itself with this 802.11 SCell. By one approach, once the UEis associated with the 802.11 access point associated with the eNB, thisassociation may either be explicitly communicated to the eNB by the UEor the eNB may know about the association state of the UE since the802.11 AP is either an internal element of the eNB or is an externalelement connected via a suitable interface. The association state willbe known at the 802.11 access point and the MAC address of theassociated UE may be passed on to the eNB for this purpose.

For enabling the option of having the UE explicitly inform the networkabout this association status, a measurement report may be triggeredupon successful association with the 802.11 access point and sent to theeNB. The eNB can infer from this measurement report that successfulassociation has been achieved. Other UE-originated messages whosesending is contingent on successful association could also be used forthis purpose (a MeasurementReport is just one illustrative example inthese regards).

By one approach the MeasurementReport message used in LTE can bemodified to accommodate such 802.11 SCell details. These changes couldfor instance be included in the MeasResults IE which is included in theMeasurementReport message as follows:

MeasurementReport (message exchanged between UE and eNB)

-   -   MeasResults        Where MeasResults can include some or all of:

MeasResults

-   -   measResultPCell    -   measResultNeighCells        -   measResultListEUTRA        -   measResultListUTRA        -   measResultListGERAN        -   measResultsCDMA2000    -   measResultServFreqList-r10    -   measResultServ802.11-r13 (new optional IE added to the        MeasResults IE)        -   BSSID of the 802.11 AP#1            -   RCPI and RSNI (corresponding to the 802.11 AP)            -   802.11 MCS scheme (an estimate of MCS scheme that could                be used for the data transfer on the 802.11 leg)            -   802.11 state {enumerated: UE 802.11 State 1, UE 802.11                State 2, UE 802.11 State 3, UE 802.11 State 4} (tells                the network whether the UE has already associated or not                with the 802.11 network controlled by the eNB)            -   802.11 channel utilization        -   BSSID of the 802.11 AP#N (similar field as above for the            N^(th) 802.11 SCell)

Upon receiving the above measurement report message, the eNB may thendecide to add the 802.11 SCell and enable the user plane data transferthus initiating TCIW operation. This step may be taken by the eNB, afterreceiving the information regarding successful association with the UE,based on certain implementation-dependent criteria such as thosementioned herein.

Addition of the 802.11 SCell can be performed using theRRCConnectionReconfiguration procedure. Once the RRC ConnectionReconfiguration procedure is complete (i.e. upon reception of theRRCConnectionReconfiguration complete message), the eNB may activate the802.11 SCell thus enabling user plane data transfer over the 802.11interface (and allowing the UE to move to a state equivalent to the802.11 state 4). Activating the SCell may be achieved using MACsignaling. The UE can now be informed that it is allowed to route dataplane over this 802.11 SCell.

As is done with the current carrier aggregation operation in LTE, theeNB may activate or deactivate an SCell that has been added for a givenUE. By deactivating the 802.11 SCell when there is no need for datatransfer, the eNB may provide the UE with a means to save batter power(by eliminating a need to monitor the 802.11 SCell). Deactivation of the802.11 SCell instead of removing it enables the eNB to reactivate it ata later stage without sending a full RRC Reconfiguration message.

By one approach the 802.11 SCell needs to be activated only when thereis data to be offloaded on to the 802.11 SCell. A UE may still stayassociated with the 802.11 SCell even when there is no user plane dataor when the SCell is deactivated. In case of normal LTE SCell operation,this is achieved using MAC signaling. The present teachings willaccommodate a procedure similar to this but adapted to 802.11 operationto provide for activation and deactivation of an 802.11 SCell.

To control the activation and deactivation of the 802.11 SCell, theexisting Activation/Deactivation MAC CE could be used (see, for example,3GPP TS 36.321). Existing MAC CE practices would, however, eitheractivate or deactivate both the uplink and downlink of the specifiedSCell. There may be situations where the network may want to control theUE's transmissions on the uplink. A semi-static mechanism of controlover uplink transmissions may be achieved by activating and deactivatinguplink and downlink links separately. New MAC CEs could be used toachieve this. Referring generally to the process 900 shown in FIG. 9,such MAC CE-based signaling may be used to toggle the UE between stateswhich do/do not permit user plane data transfer. Specifically, the UEcan be moved to a state equivalent to the 802.11 state 4 upon activationof a given 802.11 SCell and then moved to a state equivalent to the802.11 state 3 upon deactivation.

As shown above, the activation and deactivation of the 802.11 SCell maydepend on implementation-dependent criteria. For instance, the networkmay decide to activate or deactivate the SCell based on one or acombination of factors of choice including various factors as areidentified herein.

There may be instances when the UE cannot comply with the MAC CEactivating data transmission on a given 802.11 SCell. In this case, theUE may need to inform the eNB that it cannot use its 802.11 hardware forTCIW operation. By one approach the UE can send a new MAC CE to the eNBto specifically communicate such a situation. The information may bespecific to only the uplink, only the downlink, or to both the uplinkand the downlink.

In these examples the LTE PCell acts as the mobility anchor and alsoterminates the RLC and PDCP layers in the user plane. Hence, it can beuseful that the UE communicates with the LTE PCell in order for it toexchange data with the eNB. Accordingly, if the UE loses communicationwith the LTE PCell or if there is a handover from one eNB to another(and hence a change in the LTE PCell), then the present teachings willaccommodate releasing the 802.11 SCell. If appropriate a new 802.11SCell can then be added after re-establishing the connection on thetarget LTE PCell (target eNB). In order to facilitate a quick additionof the new 802.11 SCell, details of the 802.11 SCell (such as BSSID,802.11 band or channel, and so forth) controlled by the target LTE eNBmay be provided in the handover command (the information being provided,for example, by the target eNB).

Depending on the relative sizes of the LTE and WLAN coverage areas, itmight be more common for the UE to move in and out of 802.11 coveragewhilst it is associated with a given eNB. The measurement reportingprocedure can be used by the LTE PCell as a means to understand thequality of the 802.11 SCell (in the case of the network controlledoption) and the association status of the UE (in the case of the UEcontrolled option). Thus, in both cases, the eNB is eventually madeaware of the state of the UE's connection with the 802.11 access pointusing the measurement reporting procedure. The network may then usevarious criteria in addition to the information contained in the UE'smeasurement reports to decide when to add/remove the 802.11 SCell.

The RLC transmitter entity in the case of downlink traffic resides inthe eNB and in the case of the uplink resides in the UE. Both the LTEand 802.11 MAC entities in either the eNB or UE may visit their localRLC entity to pull data of a given size ready for transmission. In thecase of LTE MAC, the pulled data depends on the grant size (asdetermined by the LTE MAC scheduler entity in the eNB and which may forexample be based on UE Channel Quality Indications (CQI) or buffervolume information). In the case of the 802.11 MAC, a pseudo grant sizemay be indicated to the LTE RLC entity (to conceal from the RLC the factthat it is in fact an 802.11 MAC that exists below it and thereby tominimize impacts to the existing RLC layer design).

By one approach this pseudo grant size may be preconfigured. For examplethe pseudo grant size may have a value that is fixed and in the regionof an IP packet size such as 1500 bytes (which is a size that the 802.11MAC is used to handling).

By another approach this pseudo grant size may be calculateddynamically, either by the 802.11 MAC/LLC or an inter-AT schedulinglayer such as the 802.11ak and/or an 802.1AC protocol layer, based on anumber of factors (solely or in combination) such as:

-   -   Any available 802.11 air interface metric (available over an SAP        provided by a protocol layer such as the 802.11ak and/or        802.1AC). Examples of 802.11 air interface metrics include (mean        throughput available on the 802.11 side, a measure of 802.11        load, Contention Window/Backoff-Window sizes on the 802.11 side,        current MCS operational in the 802.11 side, and mean MAC delay        on the WLAN side);    -   QoS parameters of the active traffic;    -   An allowable medium occupancy threshold or value (it may be        desirable to limit the degree to which the 3GPP system accesses        the unlicensed spectrum in order to constrain its impact on        other users or systems); and    -   An allowable maximum packet duration (e.g. it may be desirable        to avoid longer packets in the case of highly latency sensitive        services, or to ensure that not too much data transfer is        attempted via the 802.11 leg in scenarios where there is a high        probability of contention on the medium-high load).

By another approach the eNB (perhaps using one or more of the factorsabove) could send enough data to the 802.11 MAC such that thetransmission over the physical layer is expected to take a predeterminedperiod of time (for instance, 1 ms transmission time over the air couldbe targeted to match the LTE TTI length and current LTE schedulinggranularity). The amount of data to provide to the 802.11 MAC would thendepend on the mean throughput on the 802.11 side, number of users to beserved, expected contention/backoff periods, 802.11 MCS, and so forth.These parameters may be extracted from the 802.11 MAC/Phy or provided byan intermediate protocol layer such as 802.11ak and/or 802.1AC.

With reference to the architectural representation 1000 shown in FIG.10, the LTE MAC entity may visit the local RLC entity synchronouslyevery 1 ms to pull down data of the “grant” size as per the current LTEoperation. Also, the MAC entity may visit the RLC entity asynchronously,whenever the 802.11 MAC has finished transmission of its last frame, topull the next set of RLC PDUs of the pseudo grant size to be transmittedover the 802.11 interface. To enable this, an intermediate protocollayer such as the 802.11ak or 802.1AC can provide an indication to theRLC layer upon the 802.11 finishing transmission of the previous frame.The RLC entity can either assemble new RLC PDU(s) (from the bufferedPDCP data) or segment or concatenate RLC PDU(s) from the retransmissionbuffer (in case of RLC AM) and pass the RLC PDU(s) to the lower layerfor transmission over the 802.11 interface.

Referring generally to the architectural representation 1100 shown inFIG. 11, an alternative approach to the above is to use theinter-Access-Technology (inter-AT) scheduling layer as an intermediatelayer between the MAC and RLC layers. This inter-AT scheduling layer mayact completely transparently to the LTE MAC whilst it may interface withthe 802.11 MAC such that it presents itself to the RLC layer above asanother LTE MAC layer. For instance, this layer may visit the RLC layersynchronously at 1 ms time intervals and pull and buffer RLC PDUs fortransmission through the 802.11 SCell. Some or all of the servicesprovided by this inter-AT scheduling layer may be incorporated into aprotocol layer such as the IEEE 802.11ak and/or IEEE 802.1AC.

In the case of LTE, the eNB scheduler knows the amount of data in the UEbuffer based on the received BSR from that UE. The eNB schedules a givenUE on the uplink by granting uplink resources for transmission. The eNBhence can update its own understanding of pending uplink data based onthe indicated BSR and the size of uplink grants sent to the UE. When,however, both the LTE PCell and the 802.11 SCell are enabled, the eNBmay not be able to keep track of the amount of pending uplink data atthe UE based on the BSR and the history of grants on the LTE sidebecause the UE may also be autonomously sending uplink data withoutexplicit grants using the 802.11 SCell.

Accordingly, by one approach, when the UE provides a BSR it reports allthe data it has buffered to the eNB and the eNB takes into account theuplink data it has successfully received both on the LTE PCell and onthe 802.11 SCell in calculating the current pending uplink data in theUE buffer. The eNB can then make an appropriate resource grant to theuplink LTE MAC.

Even though the UE reports all the pending data in the BSR, the eNB maychoose not to send a grant (or enough grants to clear the pending datain the buffer) on the LTE PCell, thereby implicitly indicating to the UEthat the UE is expected to send all (or most of) the data via the 802.11SCell. This may be acceptable for certain applications that areoperating on a best-effort basis. For applications that require aminimum QoS guarantee, however, this may not be suitable if the datarate on the 802.11 SCell falls below a necessary correspondingthreshold. In this case, the UE may indicate to the network a need foran improved level of service via the 802.11 SCell. A new MAC CE may beused to indicate such a state. As an alternative, the UE can also send aUE assistance message indicating that a power optimized configuration isnot preferred (i.e. QoS should be prioritized over power consumption).

By another approach the UE can estimate the proportionate throughput itwould expect to achieve on the 802.11 SCell based on factors likecurrent MCS, loading on SCell, or a historical measure of throughput onthe 802.11 SCell (to note but a few useful examples in these regards)and modify accordingly the volume of traffic that it reports in the BSRso that the LTE MAC scheduler will only see the remaining data volumethat would actually be sent on the LTE PCell. For example, if the devicehad measured a throughput on 802.11 over a predetermined period of time(such as the last 10 seconds) of 1 Mbit/s and a throughput on LTE of 0.5Mbit/s, then 802.11 is accounting for ⅔ of the device throughput and LTEis accounting for ⅓ of device throughput. If there are 10 kbytesbuffered then the device would report a traffic volume of 3.33 kbytes inits BSR to the LTE PCell and would expect that the 802.11 leg will beable to serve the remaining 6.67 kbytes of data. If during the transferof the data the throughput over 802.11 or LTE were to changesignificantly (for example, beyond a predetermined threshold) then a newBSR may be triggered again to account for the change in the situation.For instance, the UE may keep track of its indicated BSR size to the LTEleg and if the total data scheduled over LTE uplink equals or exceedsthe indicated BSR size (whilst there is still some pending data in theUE buffer—i.e. the data rate over LTE leg becomes faster than expectedor the data rate over 802.11 leg becomes slower than expected) then theUE may indicate a new BSR to the eNB.

By one approach at least some of the foregoing options can furtherinclude having the UE mark a set of PDUs (for which an LTE uplinkresource has been granted as being not for 802.11 SCell scheduling).When the 802.11 MAC next inspects the queued traffic to pick the nextRLC PDU(s) for scheduling over the 802.11 SCell, it would know not topick one of the RLC PDUs/IP packets that are so marked.

Referring generally to the architectural representation 1200 shown inFIG. 12, the RLC transmitter entity in the case of uplink resides in theUE. The handling of data at the RLC is very similar to the downlink.FIG. 12 illustrates specifically an uplink transmission when there is no(asynchronisity-hiding) inter-AT scheduling layer between the RLC andthe MAC entities. In the case of 802.11 SCell uplink activity, the grantsize is a pseudo-grant size as determined by the UE as described above.The UE then assembles an 802.11 MAC PDU as per that pseudo grant size.The UE may apply the current logical channel prioritization rules (see3GPP TS 36.321) to populate the MAC PDU with data from different logicalchannels and pass this on as the 802.11 MAC data frame for transmission.

The architectural representation 1300 shown in FIG. 13 depicts theuplink handling with an inter-AT scheduling layer between the RLC andMAC entities (to hide from the RLC layer the asynchronous nature of the802.11 MAC). Some or all of the services provided by this inter-ATscheduling layer may be incorporated into a protocol layer such as IEEE802.11ak and/or IEEE 802.1AC.

In a system in which a radio bearer could be mapped to either WLAN or3GPP, it may be desirable to allow configuration of whether a particularradio bearer may be routed over only LTE CCs (i.e. LTE PCell and itscomponent carriers and any LTE SCell and its component carriers), onlyover 802.11 SCell(s), or over a mixture of LTE CCs and 802.11 SCell(s).Alternatively, the configuration could be defined to indicate whether aparticular radio bearer may be routed over only licensed carriers, onlyover unlicensed carriers, or over a mixture of both licensed andunlicensed carriers.

The configuration of the bearer could be determined either at the eNBbased on the received QoS information of the bearers whilst they aresetup or the core network node (MME) may explicitly indicate this whenthe bearer is setup. This may for instance be based on subscriptiondata. Alternatively this may be done per UE or per eNB. The option forthe explicit indication from the core network would likely involve newsignaling between the MME and the eNB.

Table 1, shown below, presents a message to be sent by the MME and isused to request that the eNB assign resources on Uu and S1 for one orseveral E-RABs.

TABLE 1 MME message IE type and Semantics Assigned IE/Group NamePresence Range reference description Criticality Criticality MessageType M 9.2.1.1 YES reject MME UE S1AP ID M 9.2.3.3 YES reject eNB UES1AP ID M 9.2.3.4 YES reject UE Aggregate Maximum O 9.2.1.20 YES rejectBit Rate E-RAB to be Setup List 1 YES reject >E-RAB To Be Setup 1 . . .<maxnoofE- EACH reject Item IEs RABs> >>E-RAB ID M 9.2.1.2 — >>E-RABLevel QoS M 9.2.1.15 Includes — Parameters necessary QoSparameters. >>Transport Layer M 9.2.2.1 — Address >>GTP-TEID M 9.2.2.2EPC TEID. — >>NAS-PDU M 9.2.3.5 — >>Correlation ID O 9.2.1.80 YESignore >>SIPTO Correlation O Correlation ID YES Ignore ID9.2.1.80 >>E-RAB Routing O ENUMERATED — (Licensed carriers only,Unlicensed carriers only, Licensed and unlicensed carriers)

As a further alternative, a new type of radio bearer configuration couldbe defined to indicate “Mixed mode radio bearer” wherein it could bestated in the corresponding specifications that RLC PDUs of this radiobearer type may be transmitted over either 802.11 (e.g. unlicensed) orLTE (e.g. licensed).

By one approach, when scheduling PDUs of a bearer over either licensedor unlicensed spectrum, the MAC of the chosen access technology couldcontinue attempting to transmit a data packet (e.g. MAC SDU) until ithas run out of time (e.g. a defined time period measured inmilliseconds) or until a maximum number of re-transmission attempts havebeen made, at which point the data packet/MAC SDU could be discarded.The associated max-time or max-retry value could be preconfigured (e.g.specified in the corresponding specifications) or derived autonomouslyby the eNB or UE (e.g. based on the QCI assigned to the radio bearer(s)in question), or could be signaled to the UE or eNB from another networkentity (e.g. a core network node in EPC). As a further possibility, theeNB could derive the max-time or max-retry value (e.g. based on theQCIs) and could signal this value to the UE to use for its uplinktransmissions. The eNB may signal these values to the UE in the MACconfiguration for the 802.11 SCell.

By one approach the network controls whether the UE is allowed to steertraffic of a given bearer to 802.11 SCell or not. In some cases, it maybe beneficial to base this decision on a per UE basis. This decision canbe based, for example, on the subscription data available at the corenetwork. For example, if the UE is subscribed for offloading to an802.11 SCell when available then the UE may be configured with TCIWoperation. If the subscription data doesn't allow this, then the UE willnot be configured with an 802.11 SCell and hence TCIW operation will benot possible.

Such per-UE signaling may also be sent from the core network node to theeNB. Also, the control may be based on a per-eNB basis (i.e. an eNB mayor may not be allowed to resort to TCIW operation under the control ofthe core network). Specific signaling between the core network nodes andthe eNB may be provided to enable per-UE level control and/or per-eNBlevel control of TCIW operation.

If this general approach were to be used for supporting delay-sensitivetraffic, by one approach a mechanism could be provided to ensure thatthe resulting RLC PDU loss rate (due to the packet discards) does notbecome too excessive. Such a mechanism could comprise providing somefeedback from the 802.11 MAC into the Inter-AT scheduling layer toinform the Inter-AT scheduling layer of any MAC PDU discarding and/orproblems/delay in transferring data. If packet loss rate/re-transmissionrate/delay becomes too high then the Inter-AT scheduling layer couldstart diverting RLC PDUs of delay sensitive mixed mode bearers to LTE.

If this approach were adopted a mechanism might also be further utilizedto ascertain when the traffic of delay-sensitive mixed-mode bearers(i.e. a bearer that had been re-routed over LTE) could once again startto have frames carried over 802.11. One option could be to monitortransmission performance of non-GBR traffic that is being carried overunlicensed spectrum for that user. If non-GBR traffic is being conveyedwith low delay (and/or without excessive retransmission) then theInter-AT scheduling Layer could start again to route delay sensitivetraffic towards the 802.11 MAC. Another option would be to attemptsending the occasional real-time bearer associated RLC PDU (such asevery 10^(th) or every 100^(th) PDU) over WLAN and monitor the resultingperformance to see whether it is conveyed sufficiently quickly. If theresults appear at least adequate then a greater proportion of GBRtraffic could be routed towards 802.11.

By another approach to scheduling PDUs of a bearer over either licensedor unlicensed 802.11, an RLC PDU (for either uplink or downlink) isforwarded initially to the 802.11 MAC for transmission. If the 802.11MAC fails to deliver the PDU within a sufficient (pre-determined) time(or within a pre-determined number of transmission attempts) the 802.11MAC gives up trying to transmit the PDU. If desired, instead ofdiscarding the PDU the PDU is returned to the (transmit side) RLC andmarked as being for transmission on LTE (the marking could also includesome indication of the urgency with which LTE should send the packet).

The associated max-time or max-retry value could be derived autonomouslyby the eNB or the UE based, for example, on the QCI assigned to theradio bearer(s) in question. By another approach this information couldbe signaled to the UE or eNB from another network entity (such as a corenetwork node in EPC). As a further possibility, the eNB could derive themax-time or max-retry value (based, for example, on the QCIs) and couldsignal this value to the UE to use for its uplink transmissions. Thereverse situation could also be supported (i.e. if LTE fails to deliverthe RLC PDU within a given time then the RLC PDU could be returned tothe RLC and marked for transmission on 802.11).

The signaling used in configuring the radio bearer may therefore alsoindicate to the UE and/or the eNB how long an attempt could be made totransmit an RLC PDU on the first access technology (or for how manyretries) before the attempt should be aborted and a re-attempt madeusing the second access technology. (Those skilled in the art willunderstand and appreciate that this mechanism purely concerns behaviorat the MAC layer and does not rely on presence or acknowledgements atthe RLC layer.)

The present disclosure may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the disclosure is, therefore,indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. An apparatus comprising: a control circuitconfigured to: determine that a wireless device currently being servedvia licensed wireless spectrum could also be served via unlicensedwireless spectrum; transmit a first Radio Resource Control (RRC) messageto configure the wireless device to make measurements on the unlicensedwireless spectrum; receive a second RRC message from the wireless devicewherein the second RRC message includes the measurements on theunlicensed wireless spectrum; add a network node to enable user planedata traffic between the network node and the wireless device over theunlicensed wireless spectrum; send a third RRC message to the wirelessdevice wherein third RRC message includes parameters for the wirelessdevice to connect to the unlicensed wireless spectrum; receive from thewireless device a fourth RRC message confirming that the wireless devicehas successfully connected over the unlicensed wireless spectrum whereinthe fourth RRC message is a RRCConnectionReconfigurationComplete messagecomprising at least a media access control (MAC) address of the wirelessdevice enabling the apparatus to implement inter protocol layerbindings, and wherein the RRCConnectionReconfigurationCompletcompletemessage causes the apparatus to activate the network node.
 2. Theapparatus of claim 1, wherein the apparatus comprises an Evolved Node-Bbase station in a Long Term Evolution (LTE) Radio Access Network (RAN).3. The apparatus of claim 2, wherein the network node operating in theunlicensed wireless spectrum comprises an 802.11-compatible wirelesslocal area network node.
 4. The apparatus of claim 1, wherein thecontrol circuit is further configured to: receive from the wirelessdevice information regarding at least one of: present availability ofthe unlicensed wireless spectrum; signal level as corresponds to theunlicensed wireless spectrum; signal quality as corresponds to theunlicensed wireless spectrum; and estimated throughput as corresponds tothe unlicensed wireless spectrum.
 5. The apparatus of claim 1, whereinthe third RRC message includes at least one of an identity of thenetwork node and information regarding capabilities of the network node.6. The apparatus of claim 5, wherein the identity of the network nodeincludes one of: SSID; BSSID; HESSID; and MAC address.
 7. The apparatusof claim 1, wherein the third RRC message is anRRCConnectionReconfiguration message.
 8. The method of claim 1, whereinan uplink and a downlink of the network node are activated separate fromeach other utilizing Media Access Control (MAC) control elements.
 9. Amethod comprising: by a control circuit: determining that a wirelessdevice currently being served via licensed wireless spectrum could alsobe served via unlicensed wireless spectrum; transmitting a first RadioResource Control (RRC) message to configure the wireless device toconnect to make measurements on the unlicensed wireless spectrum;receiving a second RRC message from the wireless device, wherein thesecond RRC message includes the measurements on the unlicensed wirelessspectrum; adding a network node to enable user plane data trafficbetween the network node and the wireless device over the unlicensedwireless spectrum; sending a third RRC message to the wireless device,wherein the third RRC message includes parameters for the wirelessdevice to connect to the unlicensed wireless spectrum; and receivingfrom the wireless device a fourth RRC message confirming that thewireless device has successfully connected over the unlicensed wirelessspectrum, wherein the fourth RRC message is aRRCConnectionReconfigurationComplete message comprising at least a mediaaccess control (MAC) address of the wireless device enabling theapparatus to implement inter protocol layer bindings, and wherein theRRCConnectionReconfigurationCompletcomplete message causes the controlcircuit to activate the network node.
 10. The method of claim 9, whereinthe control circuit comprises an Evolved Node-B base station in a LongTerm Evolution (LTE) Radio Access Network (RAN).
 11. The method of claim10, wherein the unlicensed wireless spectrum comprises an802.11-compatible wireless local area network.
 12. The method of claim9, further comprising: receiving from the wireless device informationregarding at least one of: present availability of the unlicensedwireless spectrum; signal level as corresponds to the unlicensedwireless spectrum; signal quality as corresponds to the unlicensedwireless spectrum.
 13. The method of claim 9, wherein the third RRCmessage includes at least one of an identity of the network node andinformation regarding capabilities of the network node.
 14. An apparatuscomprising: a Long Term Evolution (LTE)-compatible wireless transceiverthat employs licensed wireless spectrum to communicate with an LTE basestation; an unlicensed wireless spectrum transceiver that employsunlicensed wireless spectrum to communicate with a Wireless Local AreaNetwork (WLAN) access point; and a control circuit operably coupled tothe LTE-compatible wireless transceiver and the unlicensed wirelessspectrum transceiver and configured to: receive from the LTE basestation a Radio Resource Control (RRC)-based message to cause theapparatus to connect to the WLAN access point, wherein the WLAN accesspoint is identified by a RRC-based message; associate with the WLANaccess point in response to the RRC-based message having been received;and transmit a RRC complete message to the LTE base station in responseto associating with the WLAN access point, the RRC complete messagecomprising unlicensed wireless spectrum capabilities of the apparatus,measurement results from one or more measurements performed by theapparatus with respect to the WLAN access point, and a media accesscontrol (MAC) address of the apparatus enabling the LTE base station toimplement inter protocol layer bindings, wherein the RRC completemessage causes the LTE base station to activate the WLAN access point,and wherein activating the WLAN access point enables user plane datatransfer between the apparatus and the WLAN access point over theunlicensed wireless spectrum.
 15. The apparatus of claim 14, wherein theapparatus comprises a wireless portable electronic device.
 16. Theapparatus of claim 14, wherein the unlicensed wireless spectrumcomprises an 802.11-compatible wireless local area network.
 17. Theapparatus of claim 14, wherein the control circuit is further configuredto provide to the LTE base station, via an RRC-based message,information regarding at least one of: present availability of theunlicensed wireless spectrum; signal level as corresponds to theunlicensed wireless spectrum; signal quality as corresponds to theunlicensed wireless spectrum.
 18. The apparatus of claim 14, wherein theRRC message includes at least one of an identity of the unlicensedwireless spectrum transceiver and information regarding capabilities ofthe unlicensed wireless spectrum transceiver.
 19. A method comprising:by a control circuit of a wireless device that operably couples to aLong Term Evolution (LTE)-compatible wireless transceiver employinglicensed wireless spectrum to communicate with an LTE base station andto an unlicensed wireless spectrum transceiver that employs unlicensedwireless spectrum to communicate with a Wireless Local Area Network(WLAN) access point: receiving from the LTE base station a RadioResource Control (RRC)-based message to cause the control circuit toconnect to the WLAN access point; associating with the WLAN access pointin response to the RRC-based message having been received; andtransmitting a RRC complete message to the LTE base station in responseto with the associating with the WLAN access point, the RRC completemessage comprising a media access control (MAC) address of the wirelessdevice enabling the LTE base station to implement inter protocol layerbindings, wherein the RRC complete message causes the LTE base stationto activate the WLAN access point, and wherein activating the WLANaccess point enables user plane data transfer between the controlcircuit and the WLAN access point over the unlicensed wireless spectrum.20. The method of claim 19, wherein the control circuit comprises awireless portable electronic device.
 21. The method of claim 19, whereinthe unlicensed wireless spectrum comprises an 802.11-compatible wirelesslocal area network.
 22. The method of claim 19, further comprising:providing to the LTE base station, via an RRC-based message, informationregarding at least one of: present availability of the unlicensedwireless spectrum; signal level as corresponds to the unlicensedwireless spectrum; signal quality as corresponds to the unlicensedwireless spectrum.
 23. The method of claim 19, wherein the RRC messageincludes at least one of an identity of the unlicensed wireless spectrumtransceiver and information regarding capabilities of the unlicensedwireless spectrum transceiver.